Texas -- A "secret" interstate (Signed as US 54), existing only on federal rolls and some maps. However, it was signed as I-110 until the US 54 freeway north of I-10 opened; then I-110 became US 54. It is only 0.94 miles in length.

Louisiana -- It runs runs north from I-10 in Baton Rouge and was completed around 1984. It is 8.89 miles in length.